Developer Reference for Intel® oneAPI Math Kernel Library - C

Developer Reference

  • 2021.1
  • 12/04/2020
  • Public Content
Contents

p?lasnbt

Computes the position of the sign bit of a floating-point number.

Syntax

void
pslasnbt
(
MKL_INT
*ieflag
);
void
pdlasnbt
(
MKL_INT
*ieflag
);
Include Files
  • mkl_scalapack.h
Description
The
p?lasnbt
function
finds the position of the signbit of a single/double precision floating point number. This
function
assumes IEEE arithmetic, and hence, tests only the 32-nd bit (for single precision) or 32-nd and 64-th bits (for double precision) as a possibility for the signbit.
sizeof(int)
 is assumed equal to 4 bytes.
If a compile time flag (
NO_IEEE
) indicates that the machine does not have IEEE arithmetic,
ieflag
 = 0
 is returned.
Output Parameters
ieflag
This flag indicates the position of the signbit of any single/double precision floating point number.
ieflag
 = 0
, if the compile time flag
NO_IEEE
 indicates that the machine does not have IEEE arithmetic, or if
sizeof(int)
 is different from 4 bytes.
ieflag
 = 1
 indicates that the signbit is the 32-nd bit for a single precision
function
.
In the case of a double precision
function
:
ieflag
 = 1
 indicates that the signbit is the 32-nd bit (Big Endian).
ieflag
 = 2
 indicates that the signbit is the 64-th bit (Little Endian).

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.